Atypical ("pseudosarcomatous") cutaneous histiocytoma

Area of Science:

• Dermatopathology
• Surgical Pathology
• Histopathology

Background:

• Hemosiderotic histiocytoma is a rare cutaneous lesion.
• Cytological atypia can complicate histological diagnosis.
• Distinguishing benign lesions from malignancy is crucial in surgical pathology.

Observation:

• A case presented with a lesion cytologically atypical and histologically suspicious for sarcoma.
• The lesion was carefully differentiated from atypical fibroxanthoma and fibroxanthosarcoma.
• Microscopic examination revealed features of hemosiderotic histiocytoma.

Findings:

• The histological features, despite significant cellular atypia, were consistent with a benign hemosiderotic histiocytoma.
• The lesion was definitively distinguished from malignant sarcomas like fibroxanthosarcoma.
• This case highlights a variant of hemosiderotic histiocytoma with marked atypia.

Implications:

• Emphasizes the benign nature of this specific variant of hemosiderotic histiocytoma.
• Highlights the importance of careful histopathological evaluation to avoid misdiagnosis of sarcoma.
• Provides diagnostic criteria for differentiating this benign entity from malignant mimics in dermatopathology.